June 2011

Document Type


Degree Name



Dept. of Public Health & Preventive Medicine


Oregon Health & Science University


Background Patients with acute respiratory tract infections (RTIs) frequently present to primary care clinics. Most of these infections are caused by viruses and are not treatable with antibiotics. Their overuse can result in adverse patient health effects and increase community antibiotic resistance. Antibiotic over-prescribing was suggested by a preliminary study of three Portland Veteran Administration Medical Center (PVAMC) community based outpatient clinics (CBOCs). This retrospective study of the same time period (July 1, 2008 to June 30, 2009), augments that study with the addition of patients who presented with acute (RTIs) at the remaining four PVAMC CBOCs. Methods Electronic medical records (EMR) were assembled using the International Statistical Classification of Diseases (ICD-9) codes to include subjects with non-specific RTIs, sinusitis, bronchitis, pharyngitis, and pneumonia. Excluded ICD-9 codes were for chronic lung diseases, heart failure, and mental illnesses. Excluded also were patients who had initially presented to another healthcare facility or had symptoms lasting longer than 14 days. Eligible EMRs were abstracted for clinical signs and symptoms, pertinent laboratory results and chest x-ray findings, and antibiotic treatment. In addition to using the preliminary study data, additional details of all subject records were extracted for provider type and clinic location. All respiratory antibiotics are currently ordered via computer order entry (CPOE) in the EMR, where treatment guidelines are displayed. Abstracted clinical findings were used to derive a determination of antibiotic prescribing adherence to these guidelines. Descriptive statistics, univariate and multivariate analysis, and logistic regression (MLR) modeling characterized the predictors of antibiotic prescribing; the dependent variable of interest. The outcomes of both “over-prescribing” and “non-adherence to guidelines” were analyzed. Results This study identified 485 subjects with acute, uncomplicated RTIs having a mean age of 54.9 years and were 87% males. A diagnosis of either Sinusitis, Bronchitis, Pharyngitis, or Acute RTI, was recorded in 93% of patients. Antibiotics were prescribed for 49% of all subjects. Antibiotics were “overprescribed” (antibiotics prescribed when not recommended) for 44% of patients while overall “non-adherence to guidelines” occurred in 40% of subjects. MLR modeling with 95% Confidence Intervals (CI) for these two outcomes (over-prescribing; non-adherence) determined their respective risk factors as, advancing age (OR 1.02, CI 1.00-1.03; OR 1.02, CI 1.01-1.04), physician provider (OR 2.04, CI .883-4.72; OR 2.01, CI .885-4.56), Port/Dist…CBOC location (OR 3.56, CI 1.59-8.00; OR 2.84, CI 1.30-6.23), in addition to specific diagnoses of statistical significance. For “over-prescribing” the risk factor diagnoses were Sinusitis (OR 6.63, CI 1.77-24.8) and Bronchitis (OR 4.49, CI 1.51-13.3) while for “nonadherence” these were Bronchitis (OR 7.72, CI 3.02-19.8) and Pharyngitis (OR 3.32, CI 1.29-8.51). Inter-observer variability was analyzed using a kappa statistic (k=.236, 95% CI .000-.626) for concordance of guideline recommendation derivation. This evaluation proved insightful as to systemic issues which may be contributing to inappropriate antibiotic prescribing. Conclusions When presenting with acute respiratory infections, Veterans often receive antibiotics not indicated per guidelines. Over-prescribing and non-adherence continues despite CPOE directed guidelines according to this study. Characterizing the determinants of this inappropriate treatment should inform interventions to optimize antibiotic use in caring for area Veterans.




School of Medicine



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